Knife block for a tufting machine

ABSTRACT

A knife block for a tufting machine having provision for accurately aligning and connecting the block to an oscillating knife bar. The aligning and connecting structure includes a channel formed in the front surface of the bar, the channel being adapted to closely receive the rear edge portion of the block therein to maintain a predetermined alignment.

[ Sept. 11, 1973 United States Patent 1191 Cobble 54] KNIFE BLOCK FOR ATUFTING MACHINE 3,604,379 9/1971 Cobble...............,.1.....,.....;112/79 R FOREIGN PATENTS OR APPLICATIONS Inventor: James T. Cobble,Dalton, Ga.

932,625 7/1963 Great Britain....... 112/79 R Assignee: B & J MachineryCompany, Inc.,

Dalton, Ga.

[22] Filed: Apt 27 1972 Primary Examiner.lames R. Boler AssistantExaminer-Wai Ming Chan AttarneyFloyd A. Gibson et al.

[21] Appl. No.: 248,197

ABSTRACT 0 .m m .mmw 0k .I P3010 m c :le mm hg m m t mm m Cn o e .m m mo m mm mfw f mw yn C k m l mm .mcm i 3 7 w U. Apmo 04 0 03%0 M5 9 & ROW9 2% H W n 93 l H 2 U .1 mmh "c ""e "As L 1 C in min UIF 1]] 2 8 555[[11 [5 6 1 References Cited structure includes a channel formed in thefront surface UNITED STATES PATENTS of the bar, the channel beingadapted to closely receive the rear edge portion of the block therein tomaintain a predetermined alignment.

112/79 R 6 Claims, 3 Drawing Figures Signoret............

nil mm mm n C3 w MB 794 5 56 999 111 732 6005 922 090 076 223 KNIFEBLOCK FOR A TUFTING MACHINE The present invention relates to a tuftingmachine for forming cut pile fabric, and more particularly to the meansfor mounting the cutting knives in a tufting machine.

In the tufting industry, many varied machines have been developed forcarrying a yarn through a backing fabric to form a plurality of tuftingloops, and for severing the loops to form the cut pile. A machine ofthis type generally includes a plurality of needles for carrying theyarn strands through the backing fabric, a coopcrating looper associatedwith each needle for engaging and retaining the formed yarn loops, and aknife mounted on an oscillating knife bar for severing the yarn loopsretained on the loopers.

In tufting machines of the above described type, it is conventional forthe knife to be retained and held in a knife block, which in turn iscarried by the oscillating knife bar such that the knife is reciprocatedacross the looper with a scissors-like cutting action. Typically, theknife block is mounted on the bar by means of a laterally extendingshaft on the block which is inserted into a mating opening in the bar. Alocking set screw is provided on the bar which engages the shaft tosecure the same in the opening and thereby maintain the alignment of theblock.

The operators of such prior tufting machines have experienced difficultyhowever in initially establishing the proper alignment between the knifeblock and bar, and maintaining the alignment under the stress andvibration encountered during long periods of use. As will be apparent,any misalignment can cause serious problems since the angular alignmentbetween the knife and looper must be closely maintained to insure propercutting action. Also, it is common for the machine operator to overlytighten the locking set screw in an attempt to maintain properalignment, and this often results in damage to the shaft.

It is accordingly an object of the present invention to provide aconnecting means of the described type wherein the desired alignment maybe easily established and will be maintained under the stress andvibration encountered during long periods of use.

It is another object of the present invention to provide a connectingmeans of the described type which insures that the correct angle of theblock and knife is always maintained, and which does not require anyadditional parts over those commonly employed in mounting the block tothe bar in a conventional tufting machine. I

These and other objects and advantages of the present invention areachieved in the embodiment illustrated herein by the provision of meansfor connecting the knife block to the knife bar which includes a channelformed in the front surface of the bar, the channel being adapted toclosely receive the rear edgeportion of the knife block therein. Inaddition, a cylindrical shaft extends from the rear edge portion of theknife block, and a cylindrical opening extends into the channel on theknife bar, for closely receiving the cylindrical shaft. To lock theshaft in the opening, there is provided a threaded aperture whichextends into the bar and communicates with the cylindrical opening, anda locking screw is adapted to be threadedly received in the aperture toengage the shaft.

To assemble the knife block to the bar, the shaft of the block isinserted into the cylindrical opening of the bar until the rear edgeportion of the block is received in the conforming channel. By design,the knife carried by the block will be in the desired predeterminedposition with respect to the loopers when the block is so received inthe channel of the knife bar. The locking screw is then rotated toengage the shaft to prevent withdrawal thereof. In this position,relative rotational movement between the block and bar is precluded bythe closely conforming interconnection between the channel and blockrear edge portion, and this relationship may be maintained with verylittle tightening of the locking screw. Thus, the danger ofdisfigurement to the shaft by over tightening of the locking screw isalleviated.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds, when taken in connectionwith the accompanying drawings, in which FIG. 1 is a fragmentaryperspective view, partly sectioned, of a severing mechanism in a cutpile tufting machine and which embodies the present invention;

FIG. 2 is a fragmentary front elevational view of the knife block andbar illustrated in FIG. 1;

FIG. 3 is a fragmentary top plan view of the knife block and bar shownin FIG. 2.

Referring to the drawings, FIG. 1 illustrates a severing mechanism in anotherwise conventional cut pile tufting machine, and which embodies thefeatures of the present invention. As shown, the machine includes aplurality of reciprocating needles 10, each of which carries a yarn 11through a backing fabric (not shown) to form a plurality of tuftingloops. A plurality of loopers 12 is secured to a looper head 14 suchthat each looper is operatively associated with one of the needles toengage and retain the tufting yarn loops. A cutting knife 16 isoperatively associated with each looper to sever the yarn loops, theknives 16 being mounted for oscillatory movement in relation to theloopers. In particular, the knives are carried by a knife block 20 whichin turn is mounted on an oscillating knife bar 22. As will becomeapparent from the following description, a plurality of blocks 20 ismounted on the bar 22, with each block being carried in a predeterminedangular relationship with respect to the bar such that each knife willproperly engage the associated looper 12and sever the yarn in ascissors-like oscillating movement.

The knife block 20 comprises a generally rectangular unitary body memberhaving an I-shaped crosssectional configuration, and defines a forwardedge portion including the generally planar surface 23, and a rear edgeportion including the generally planar surface 24. A central connectingweb 25 interconnects the forward and rear portions and defines a pair ofknife mounting grooves 26 and 27. The block further includes oppositelyfacing planar side edge surfaces 29 and 30,'each of which are partiallycut away along a vertical direction to open communication with theassociated grooves 26 and 27. To secure the knives 16 in these grooves,a pair of spaced-apart slots 32 and 34 are provided which extendlaterally into the surface 23 of theforwardedge portion and intocommunication with the two grooves 26 and 27. A U-shaped clampingbracket 36 is adapted to enter the lateral slots 32 and 34 such that thelegs of the bracket will engage the two knives positioned in the groovesat two spaced locations. The bracket 36 is maintained in this positionby means of the threaded cap screw 38 which extends freely through theaperture 39 and is received in the threaded aperture 40 which extendslaterally into the forward edge portion between the two slots.

As seen in FIG. 1, the knife bar 22 is of generally rectangular crosssection, and the illustrated right angled cross section defines ahorizontal direction 42 and a vertical direction 44. In addition, thebar defines a front surface 46 having a plurality of closely spacedvertically directed channels 48 extending along the longitudinal lengththereof. Each of the channels has a U- shaped cross-sectional outlineand defines a planar medial surface 50 and opposed side surfaces 52 and53 extending perpendicularly from the medial surface 50. As seen inFIGS. 2 and 3, the side edge surfaces 52 and 53 are parallel and defineplanes which extend at an angle of about 12 from the vertical direction44 and at an angle of about from the horizontal direction 42. Thispredetermined angular relationship is typical for certain tuftingmachines and insures that the knives 16 are maintained in apredetermined relationship with respect to the loopers 12 as will becomemore apparent.

The means for connecting the knife block to the bar further includes acylindrical shaft 56 connected at one end to the lower portion of therear edge surface24 of the block 20. The shaft 56 extends outwardly fromthe surface 24 in a generally perpendicular direction, and is adapted tobe closely received in one of the cylindrical openings 58 which extendhorizontally through the bar. In particular, each of the cylindricalopenings 58 communicates with the medial surface 50 of one of thechannels 48, and extends perpendicular thereto.

in summary, it will be apparent that each channel 48 has a U-shapedcross-sectional outline defined by the planar medial surface 50 andopposed side edges 52 and 53, and the rear edge portion of each blockhas a closely conforming U-shaped cross-sectional outline defined by theplanar rear edge surface 24 and the oppositely facing side edgesurfaces29 and 30. Thus, when the shaft 56 is fully inserted in its associatedopening 58, the rear edge surface 24 of the block will closely overliethe channel medial surface 50 and the channel side edge surfaces 52 and53 will closely overlie the block side edge surfaces 29 and 30 tothereby preclude relative rotational movement between the block and barabout the axis of the shaft 56.

To secure the block against withdrawal from the bar, there is providedmeans for locking the shaft 56 in the opening 58 which comprises athreaded aperture 60 extending vertically into the bar and communicatingat substantially right angles with the opening. A threaded locking screw62 is adapted to be threadedly received in the aperture 60 and engagethe shaft 56.

From the above description, it will be apparent that the presentinvention provides a novel knife block connecting structure whereby thecutting knives 16 are automatically and accurately aligned in relationto the loopers upon the block being mounted on the bar. The connectingstructure is simple and foolproof, and does not require any additionalstructural components.

In the drawings and specification, there has been set forth a preferredembodiment of the invention, and although specific terms are employed,they are used in a generic and descriptive sense only, and not forpurposes of limitation.

That which is claimed is:

l. in a tufting machine for forming a cut pile fabric and includingmeans for carrying a yarn through a backing fabric to form a pluralityof tufting loops therein, the combination therewith of looper meansoperatively associated with said yarn carrying means for engaging andretaining the tufting loops, and means operatively associated with saidlooper means for severing the tufting loops while retained by saidlooper means and including a knife bar mounted for oscillatory movementin relation to said looper means and defining a front surface, a knifeblock defining a rear edge portion positioned opposite said knife barfrom surface, a knife carried by said knife block and adapted tocooperate with said looper means in severing the yarn loop upon relativeoscillatory movement between the knife bar and looper means, and meansfor connecting said knife block to said knife bar in a predeterminedangular relationship such that the knife is maintained in apredetermined relationship with respect to said looper means, saidconnecting means including a channel formed in said bar front surface,said channel having a crosssectional outline closely conforming to thecrossseetional outline of said block rear edge portion and closelyreceiving the same therein, a cylindrical opening extending into saidbar front surface and communicating with said channel, a cylindricalshaft having one end connected to said knife block rear edge portion andextending outwardly therefrom and closely received within saidcylindrical opening, and means for locking said shaft in said opening.

2. The tufting machine as defined in claim 1 wherein said channel has aU-shaped cross-sectional outline defining a planar medial surface andopposed side edge surfaces, said block rear edge portion has a U-shapedcross-sectional outline defining a planar rear edge surface andoppositely facing side edge surfaces, whereby said block planar rearedge surface closely overlies said channel medial surface and saidchannel side edge surfaces closely overlie said block side edge surfacesto thereby preclude relative rotational movement between said knifeblock and said knife bar.

3. The tufting machine as defined in claim 2 wherein said means forlocking said shaft in said opening includes a threaded apertureextending into said bar and communicating at substantially right angleswith said cylindrical opening, and a locking screw adapted to bethreadedly received in said threaded aperture and engage said shaft.

4. The tufting machine as defined in claim 3 wherein said cylindricalshaft and cylindrical opening define a common axis extendingsubstantially perpendicular to said channel medial surface and saidknife block planar rear edge surface.

5. The tufting machine as defined in claim 4 wherein said knife bar hasa rectangular cross-section defining a vertical direction and ahorizontal direction, and said channel side edge surfaces define planeswhich extend substantially perpendicular to said medial surface and atan angle of about 12from said vertical direction and at an angle ofabout 5 from said horizontal direction.

6. In a tufting machine for forming a cut pile fabric including meansfor carrying a plurality of yarns through a backing fabric to formplurality of tufting loops therein, looper means operatively associatedwith said yarn carrying means for engaging and retaining the tuftingloops, means operatively associated with said thereof, each of saidchannels having a U-shaped looper means for severing the tufting loopswhile recross-sectional outline, tained by said looper means andincluding a knife bar a rear edge portion on each of said knife blocks,mounted for oscillatory movement in relation to said each of said' rearedge portions defining a U- looper means, a plurality of knife blockscarried by said shaped cross-sectional outline generally conknife bar,and at least one knife carried by each knife forming to thecross-sectional outline of said block and adapted to cooperate with saidlooper means channels and closely received within one of said insevering the yarn loops upon relative oscillatory channels, movementbetween the knife bar and looper means, the a plurality of cylindricalopenings extending into improvement therein comprising 10 said bar withone of said openings communicatmeans for connecting said knife blocks tosaid knife ing with each of said channels,

bar in a predetermined angular relationship such a cylindrical shafthaving one end connected to the that the knives are maintained in apredetermined rear edge portion of each knife block and beingrelationship with respect to said looper means, said closely receivedwithin the associated cylindrical connecting means including opening,and a front surface on said knife bar, said front surface means forlocking each shaft in the associated openincluding a plurality ofclosely spaced, vertically ing. directed channels along the longitudinallength

1. In a tufting machine for forming a cut pile fabric and includingmeans for carrying a yarn through a backing fabric to form a pluralityof tufting loops therein, the combination therewith of looper meansoperatively associated with said yarn carrying means for engaging andretaining the tufting loops, and means operatively associated with saidlooper means for severing the tufting loops while retained by saidlooper means and including a knife bar mounted for oscillatory movementin relation to said looper means and defining a front surface, a knifeblock defining a rear edge portion positioned opposite said knife barfront surface, a knife carried by said knife block and adapted tocooperate with saId looper means in severing the yarn loop upon relativeoscillatory movement between the knife bar and looper means, and meansfor connecting said knife block to said knife bar in a predeterminedangular relationship such that the knife is maintained in apredetermined relationship with respect to said looper means, saidconnecting means including a channel formed in said bar front surface,said channel having a cross-sectional outline closely conforming to thecross-sectional outline of said block rear edge portion and closelyreceiving the same therein, a cylindrical opening extending into saidbar front surface and communicating with said channel, a cylindricalshaft having one end connected to said knife block rear edge portion andextending outwardly therefrom and closely received within saidcylindrical opening, and means for locking said shaft in said opening.2. The tufting machine as defined in claim 1 wherein said channel has aU-shaped cross-sectional outline defining a planar medial surface andopposed side edge surfaces, said block rear edge portion has a U-shapedcross-sectional outline defining a planar rear edge surface andoppositely facing side edge surfaces, whereby said block planar rearedge surface closely overlies said channel medial surface and saidchannel side edge surfaces closely overlie said block side edge surfacesto thereby preclude relative rotational movement between said knifeblock and said knife bar.
 3. The tufting machine as defined in claim 2wherein said means for locking said shaft in said opening includes athreaded aperture extending into said bar and communicating atsubstantially right angles with said cylindrical opening, and a lockingscrew adapted to be threadedly received in said threaded aperture andengage said shaft.
 4. The tufting machine as defined in claim 3 whereinsaid cylindrical shaft and cylindrical opening define a common axisextending substantially perpendicular to said channel medial surface andsaid knife block planar rear edge surface.
 5. The tufting machine asdefined in claim 4 wherein said knife bar has a rectangularcross-section defining a vertical direction and a horizontal direction,and said channel side edge surfaces define planes which extendsubstantially perpendicular to said medial surface and at an angle ofabout 12* from said vertical direction and at an angle of about 5* fromsaid horizontal direction.
 6. In a tufting machine for forming a cutpile fabric including means for carrying a plurality of yarns through abacking fabric to form plurality of tufting loops therein, looper meansoperatively associated with said yarn carrying means for engaging andretaining the tufting loops, means operatively associated with saidlooper means for severing the tufting loops while retained by saidlooper means and including a knife bar mounted for oscillatory movementin relation to said looper means, a plurality of knife blocks carried bysaid knife bar, and at least one knife carried by each knife block andadapted to cooperate with said looper means in severing the yarn loopsupon relative oscillatory movement between the knife bar and loopermeans, the improvement therein comprising means for connecting saidknife blocks to said knife bar in a predetermined angular relationshipsuch that the knives are maintained in a predetermined relationship withrespect to said looper means, said connecting means including a frontsurface on said knife bar, said front surface including a plurality ofclosely spaced, vertically directed channels along the longitudinallength thereof, each of said channels having a U-shaped cross-sectionaloutline, a rear edge portion on each of said knife blocks, each of saidrear edge portions defining a U-shaped cross-sectional outline generallyconforming to the cross-sectional outline of said channels and closelyreceived within one of said channels, a plurality of cylindricalopenings extending into saiD bar with one of said openings communicatingwith each of said channels, a cylindrical shaft having one end connectedto the rear edge portion of each knife block and being closely receivedwithin the associated cylindrical opening, and means for locking eachshaft in the associated opening.